With switching devices, in particular low-voltage switching devices, the current paths switch between an electrical supply device and loads and therefore their operating currents. This means that, by way of current paths being opened and closed by the switching device, the connected loads can safely be switched on and off.
The translation DE 693 04 374 T2 of the European patent EP 0 560 697 B1 has disclosed a low-voltage circuit breaker in an insulating housing, which includes a rotary contact link, a pair of fixed contacts, which pair interacts with the mentioned contact link, power supply conductors for feeding the mentioned fixed contacts, a switching shaft with a transversely running cutout for mounting, with play, the contact link, which protrudes on both sides out of the switching shaft, and at least one pair of tension springs, which are arranged between the switching shaft and the contact link. The fixed contacts are designed in such a way that they generate electrodynamic forces repelling the contact link in the direction of a repelling open position if a short-circuit current is flowing through them. The tension springs serve the purpose of ensuring a contact pressure, which is exerted by the contact link on the fixed contacts, in the closed position of the circuit breaker and at the same time of making a rotation of the contact link possible under the effect of the mentioned electrodynamic forces in the direction of the repelling open position.
The mentioned springs are arranged symmetrically on both sides of the axis of rotation of the contact link and each have an end mounted on the contact link. An opposite end of the mentioned springs is mounted on a rod, which is arranged in a latching notch of the switching shaft in such a way that it is displaceable in sliding fashion. The mentioned contact link has a pair of control cams, which are arranged symmetrically with respect to the mentioned axis and are each designed in such a way that they interact with one of the rods in the end section of the repulsive excursion of the contact link in order to brake the movement of the contact link.
An electrical low-voltage switching device, such as a circuit breaker or a contactor, for example, has, for the purpose of switching the current paths, one or more so-called main contacts, which can be controlled by one or else more control magnets or electromagnetic drives. In principle, the main contacts in this case include a movable contact link and fixed contact pieces, to which the load and the supply device are connected. In order to close or open the main contacts, a corresponding closing or opening signal is emitted to the electromagnetic drive, whereupon said contacts act with their armature on the movable contact links in such a way that the contact links perform a relative movement in relation to the fixed contact pieces and either close or open the current path to be switched. In the context of the invention made, only switching devices with a rotary contact link are taken into consideration.